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Astrophysics to be learned from observations of intermediate mass black hole in-spiral events. Alberto Vecchio Making Waves with Intermediate Mass Black Holes PennState, 20 th – 22 nd May 2004. Three classes of sources. IMBH – BH(IMBH) IMBH – IMBH SMBH – IMBH.
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Astrophysics to be learned from observations of intermediate mass black hole in-spiral events Alberto Vecchio Making Waves with Intermediate Mass Black Holes PennState, 20th – 22nd May 2004
Three classes of sources • IMBH – BH(IMBH) • IMBH – IMBH • SMBH – IMBH PennState, 20th – 22nd May 2004 A Vecchio
Some questions • Do IMBHs exist? • Demographics of IMBHs: • Masses • Spins • …. • Mass vs redshift distribution • Hierarchical clustering • Structure formation • IMBHs and their environment • Dynamical processes in clusters • BH and SMBHs studies PennState, 20th – 22nd May 2004 A Vecchio
Outline • Some jargon and fundamental scales • Sensitivity • Astronomy with laser interferometers • Information extraction: astrophysics and cosmology • Conclusions PennState, 20th – 22nd May 2004 A Vecchio
Advanced resonant 107 10510310 Msun Observational window PennState, 20th – 22nd May 2004 A Vecchio
Coalescence of binary systems f = 4 [ M (1+z) /103M ]-1 Hz f = 32 [ M (1+z) /103M ]-1 Hz [Kip’s cartoon] Long livedShort lived PennState, 20th – 22nd May 2004 A Vecchio
Sensitivity (low redshift) Optimal filtering is assumed LISA Whole coalescence Advanced LIGO In-spiral Merger: Flanagan and Hughes parameters (optimistic!); Ring-down: a/m = 0.98 PennState, 20th – 22nd May 2004 A Vecchio
Sensitivity (low redshift) Optimal filtering is assumed LIGO-I Whole coalescence Merger: Flanagan and Hughes parameters (optimistic!); Ring-down: a/m = 0.98 PennState, 20th – 22nd May 2004 A Vecchio
Sensitivity (high redshift) m1 = m2 m2 = 0.01 m1 z = 0.5 z = 0.5 z = 5 z = 5 z = 30 z = 30 PennState, 20th – 22nd May 2004 A Vecchio
ESA/NASA joint mission (launch: 2012) • ESA cornerstone mission • NASA “Beyond Einstein Initiative” mission with ConX • Space-borne laser interferometers with 5 million km arms, 30 cm diameter telescopes and 1 W lasers • Powerful GW telescope: thousands of signals at anyone time • LISA Pathfinder: technology demonstrator
Binary systems L S2 S1 m2 m1 D_L N The most general system is described by 17 parameters: Masses [2] and spins [6] Orbit [4] Sky position and distance [3] Arbitrary initial time and phese [2] Penn State, 20th – 22nd May 2004 A Vecchio
Michelson observables i = II i = I (Cutler, 1998; Tinto et al, 2000) PennState, 20th – 22nd May 2004 A Vecchio
Chirp mass and distance Physical parameters: masses and spins Signal at detector output PennState, 20th – 22nd May 2004 A Vecchio
Wave cycles Newt. 1PN tail spin-orbit 2PN spin-spin Penn State, 20th – 22nd May 2004 A Vecchio
Signal at detector output PennState, 20th – 22nd May 2004 A Vecchio
LISA motion • Two key (and distinct) motions: • LISA orbits the Sun: the signal frequency is Doppler shifted • Spacecraft constellation rotates around the normal to the detector plane: the response of the detector is not fixed, that is the antenna pattern is time dependent • The signal is therefore phase and amplitude modulated • The LISA motion is essentially what provides the detector pointing capability PennState, 20th – 22nd May 2004 A Vecchio
Induced frequency shifts Δf Δf ~fGW (vLISA/c) ~ 10-7 (fGW /1 mHz) Hz motion orientation Δf ~ 2/TLISA ~ 7 × 10-8 Hz ~1 mHz Frequency/ Hz PennState, 20th – 22nd May 2004 A Vecchio
S = S1+ S2 J = L + S -N Simple precession L (Apostolatos et at, 94; Kidder, 95) PennState, 20th – 22nd May 2004 A Vecchio
Location, orientation and spins and masses Sky location Signal at detector output PennState, 20th – 22nd May 2004 A Vecchio
Signal modulations m1 = 107 Msun m2 = 105 Msun SdotL = 0.5 S/m2 = 0.95 m1 = 106 Msun m2 = 106 Msun SdotL = 0.9 S/m2 = 0.3 (AV astro-ph/0304051) PennState, 20th – 22nd May 2004 A Vecchio
Low redshift IMBHs (cont’d) PennState, 20th – 22nd May 2004 A Vecchio
Low redshift IMBHs (cont’d) PennState, 20th – 22nd May 2004 A Vecchio
Low redshift IMBHs (cont’d) • Confirm existence of IMBH • Demographics and properties • Identify time of possible EM burst due to collision for follow-on observations but error box larger than 1 sq. degree • Studies of IMBHs and their environment are not likely PennState, 20th – 22nd May 2004 A Vecchio
High redshift IMBHs PennState, 20th – 22nd May 2004 A Vecchio
High redshift IMBHs (cont’d) PennState, 20th – 22nd May 2004 A Vecchio
High redshift IMBHs (cont’d) • Confirm existence of IMBH at high redshift • Demographics and properties • Distance known to ~1%-30% • Redshift can (in principle) be reconstructed with a fractional error ~ 10%-20% (or better, as errors on cosmological parameters decrease; Hughes, 2002) • However, weak lensing will degrade our ability of reconstructing D(z) (Markovic, 1993; Holz and Hughes, 2003) • Concrete chance of studying structure formation PennState, 20th – 22nd May 2004 A Vecchio
Some caveats • Circular orbits • Only leading quadrupole included in the amplitude: other harmonics can refine information extraction (Sintes and AV, 2000; Hellings and Moore, 2001) • For radiation at f > 5 mHz, LISA transfer function behaviour (not taken into account here) will improve parameter estimation, angular resolution in particular (Seto, 2003; AV and Wickham, 2004) • Estimate of the errors are based on Cramer-Rao bound, which is a tight lower bound for high SNR (Finn, 1992; Dhurandhar et al, 1998; Nicholson and AV, 1998) PennState, 20th – 22nd May 2004 A Vecchio
IMBH + SMBH [D = 1 Gpc; circular orbit and spinning SMBH] (Finn and Thorne, 2000) PennState, 20th – 22nd May 2004 A Vecchio
IMBH + SMBH (cont’d) (Barack and Cutler, gr-qc/0310125) [D = 1 Gpc; eccentric orbit and non-spinning SMBH] PennState, 20th – 22nd May 2004 A Vecchio
IMBH + SMBH (cont’d) (Barack and Cutler, gr-qc/0310125) [D = 1 Gpc; eccentric orbit and non-spinning SMBH] PennState, 20th – 22nd May 2004 A Vecchio
IMBH + SMBH (cont’d) (Barack and Cutler, gr-qc/0310125) [D = 1 Gpc; eccentric orbit and non-spinning SMBH] PennState, 20th – 22nd May 2004 A Vecchio
IMBH + SMBH (cont’d) • For binary systems at D ~ 1 Gpc: • IMBH and SMBH mass with fractional error < 1 part in 10,000 • Distance with fractional error < 10% • Location of the source in the sky within an error box < 0.001 srad • Spin of SMBH better than 10-4 PennState, 20th – 22nd May 2004 A Vecchio
Conclusions • GW observations: confirmation of existence of IMBH • Mass vs z(D) distribution of IMBH • Demographics of IMBH • IMBH can also provide a census of SMBHs up to z ~ a few and possibly close-by BHs • (Advanced) LIGO has a fighting chance of detecting IMBHs and measuring at least the mass PennState, 20th – 22nd May 2004 A Vecchio